Ignition device for internal-combustion engines



Aug, 27, E923,

Filed July 14, 1921 S Sheets-Sheet l IIgI /7/s/7Trof? NSY Aug., 7, H923,v MB E. H. TARTRAIIS.

IGNITION DEVICE FOR INTERNAL-COMBUSTION ENGINES Fig@ ug. 7, E923.

3,463,855 E. H. TAM-mus IGNITION DEVICE FOR INTERNAL COMBUSTION ENGINES'Filed July 14, 1921 3 Sheets-Sheet 5 @y m/C/ Patented Ang.. 7, 11923..

EUGNE HENRI TARTRAIS, 0F MAISONS-LAFFITTE, FRANCE.

IGNITION DEVICE FOR INTERNAL-COMBUSTION ENGINES.I

Application filed July 14, 1921. Serial No. 484,805.

T o all whom t may concer/n.1

Be it known that I, EUGNE HENRI 'IAR- TRAIs, citizen of the FrenchRepublic, residing at. Maisons-Laffitte, Seine-et-Oise, in the Republicof France, have invented new and useful Improvements in Ignition Devicesfor Internal-Combustion Engines, of which the following is aspecification.

My invention relates to a device for effecting the initial ignition ofthe charge in internal combustion engines wherein lliquid fuel isinjected into the working cylinder, said liquid fuel being chiey heavyoils. In such engines, the ignition is auton'iatically carried out whenin normal running, but upon starting and when the engine is cold, theignition requiring the use of an igniter I have ascertained that anignition device of this kind should comply with the followingconditions. Upon starting inasmuch as the Carburation is very imperfect,the fuel should be enabled to reach the igniter, and after the firstignitions have been effected, the gases which are in a state of whirlingmotion, this condition increasing with the speed of the engine, shouldbe prevented from directly reaching the igniter, as they wouldcool thelatter to an undue extent and the ignition would cease beforethe normaloperating conditions has been attained. When the normal Conditions ofworking have been established, it is likewise necessary to break theelec-tric current which supplied the said igniter during the starting inorder to prevent the melting of the filament.

Furthermore, @en the engine is operating at regular speed, the gases inwhirling motion now become highly heated, and all parts of the igniter`must withstand the very high temperature which will prevail.

The device tobe described hereunder is intended to provide for thesevarious conditions.

The accompanying drawings show by way of example various embodiments ofmy invention.

Fig. l is a longitudinal section of the igniter proper..

Fig. 2 shows a detailof-the filament and the coupling plugs thereof.

Fig. 3 is a section of the upper part of the engine showing the ignitionplug in position and the relief cock, this representing a two-cycleengine; the oriices for the fluid disposed at the lower end ofthe'cylinder are not shown.

Fig. 4 shows in the case of two cylinders the relief cocks with theircontrol device combined with the control device for the -igmtioncurrent, in the closed position of the cocks.

Fig. 5 shows a modiied form of the outer terminal of the ignition plug.

1 indicates a. working cylinder of the engine having moving therein thepiston 2 provided with a cylindrical extension 3, which latter isadapted at the end of the compression stroke, as herein shown, to engagean annular member 4 screwed into the combustion chamber 6. An annularspace 5 is left between the extension 3 and the bore of the member 4. 7indicates the cover of the combustion chamber and 8 the atomizing devicefor admission of liquid fuel. A water circulation 9, 9a, is providedaround the cylinder and the atomizer; the water inlet and outletorifices are not shown.

The ignition device used for the initial ignition comprises a. main body10 screwing into the chamber 6 and a metal filament 11 ofplatinum-iridium or like alloy which is mounted upon the plugs 12. Acentral conductor 13 is provided at the end thereof with a head 37resting upon an insulating bushing 14 of quartz, steatite, or the like,the said conductor being surrounded by an insulating sleeve of plasticmaterial 15 such as asbestos, and by a like sleeve 15a which is held bya pressing member or follower 16. The insulating washer 17 o-f asbestos,mica or the like is used to insulate the member 16 from the main body 10of the igniter. A spring 18 bears upon the said pressing member andmaintains the conductor 13 in position, the said spring pressing againsta washer 19 which forms at the same time a spring terminal for holding awire connector.

In the wall of the cylinder is disposed a relief cock 20 for connectingthe interior of the cylinder with the exhaust chamber 23 through thepassages 21, 22. The passage 21 is closed by the piston in the positionhere represented. The distance .fr correspends to about 1l the stroke.The relief cock 20 of each cylinder is provided with the control lever24. In the example here represented wherein the engine has twocylinders, the levers 24 of the two cocks are connected together by arod 25 (Fig.v4). The cable 26 provided with the ring 26 are used to drawupon the said rod in order to open the said cocks, the latter beingreturned to their closed position by the spring 27. The rod 25 actuatesa switch lever 29 carrying a carbon brush 30 which may contact withan.insulated Contact piece 31 which is connected for instance with thenegative pole of a battery.

Before explaining the operation of the device, it is preferable to setforth the working of the engine under the normal running conditions. Theengine of the two-cycle or four cycle type takes in air exclusively intothe cylinder in the first place, this air being then strongly compressedin the cylinder on the return stroke of the piston. When the piston hasmade about 0.93 of its stroke, or in other words when the crank issituated at about 25, before the inner dead point, the edges 32 and 33will reach the same level as shown in the broken lines Fig. 3 and theair contained in the chamber 34 thus temporarily formed between thepiston and the end of the cylinder will be violently impelled into thecombustion chamber through the annular space 5 vand will assume whirlingmotion according to the arrows 35. During this transfer, the atomizer 8projects a spray of liquid fuel according to the arrows 36 in an equaldistribution about the axis thereof. This fuel, which is admittedwithout air, on the solid injection principle, is taken up by theannular air stream 5 and drawn into the portion in whirling movement 35.The more volatile portions are at once vaporized and mixed with the air.The portions still in the liquid state are projected by centrifugalforce against the walls of the chamber which are in a highly heatedstate in the absence of any water circulation; the said portions arethereby vaporized in turn and the gases thus formed becomes included inthe moving current 35. At this time, under the combined action of theheat of compression and that of the walls, the ignition takes place,giving rise to a substantially isopleric combustion. The cycle is then'completed in the known manner.

It will be observed that these conditions of operating are veryunfavorable for the starting of the engine. The latter being cold atthis moment, a small part of the fuel is vaporized instantly'while theremainder is projected against the cold wall and is thus lost. Thesedrawbacks have been obviated by the following dispositions where` withina recess 42 and thus removed from the whirling air, and as soon as thefuel reaches this small chamber it becomes vaporized and is ignited. 'Asmall explosion takes place in this side recess, and a flame is therebyprojected into the main chamber which will be enabled to ignite the fuelconta-ined therein in the liquid state but in a state of sufficientlyfine division. rlhe imperfect combustion which ensues will however besufficientto enable the engine to rotate without load, and at eachsucceeding instant the combustion effects will become better by reasonof the very rapid heating of the walls of the combustion chamber whichare purposely made thin.

The first ignition effects are obtained in this manner but as the speedincreases, it becomes necessary, as stated in the introduction, that thewhirling air shall not be directed upon the igniter to such an extent asto extinguish the same,'but nevertheless the fuel mixture should flow atleast slightly over it in order to renew the surrounding air. Thisresult is still obtained by reason of the location of the ignition plug.The gas stream 35 flows in fact parallel to the entrance of the recess42, and the gases around the filament 11 are renewed simply by theslight movement or eddies in the fluid which takes place at theentrance. Experiments will readily show the most favorable distancewhich the filament should be inserted into the said recess.

When the temperature rises in the combustion chamber, .it becomesnecessary to break the electric current passing in the filament,inasmuch as the latter would be heated by two different sources andwould soon become melted irrespectively of the alloy which was used. Toprevent any neglect in breaking the current, the control of the reliefcock is combined with the control of the ignition switch, as shown inFig. 4. In this manner the ignition current is necessarily broken uponclosing the said cock. It will be observed that it is hardly possiblethat the operator would forget to close the cock, inasmuch as the enginecould not be used under these conditions, and moreover, as in theexample herein represented, the cock may be provided with aspring-controlled closing ydevice and opened for instance by means of acable provided witha ring for hand control. Even in case the operatorshould see fit to draw upon the ring for an indefinite length of time orto attach the same, this would have no effect upon the ignition device,for the heat supplied to the filament under these conditions is notsufficient to melt the same.

On the other hand, the ignition device itself is constructed in aspecial manner whereby it is enabled to withstand very hightemperatures. When the combustion Lacasse chamber is raised to a redheat, the ignition device thus exposed will be likewise heated toredness. Although no exact measurements of temperature have been made,it appears probable that the forwardly situated portions reach or exceed1000 degrees C. as observed by the color of the visible parts. Underthese conditions it is evident that special precautions will benecessary in order that the device shall have a sufficient mechanicalstrength and shall not be subject to oxidation, and that it shall beHuidtight and electrically insulated.

The insulation is herein facilitated in a satisfactory manner by reasonof the very be observed in F ig. l that the insulating ring 14 which isproduced by machine and ground as in the case of a mechanical piece 1sdisposed and adjusted in a recess formed in the end of the main body 10.The central conductor, which is made of a special alloy as for the mainbody, is itself fitted in the ring 14 with only the necessary play, notshown, to provide for the expansion thereof. The head 37 thereof whichis fitted closely upon the end of said ring is caused to enter to afairlv considerable extent into the said recess in order to providebetween the two metal pieces, the main body and the insulated centralconductor, a certain play 38 which is made as small as possi-ble. Theeffect of this arrangement upon the electrical insulation will be setforth hereunder.

`From a mechanical standpoint, the advantages are at once apparent.Should the ring 14 be brokemthe pieces which might fall into the enginewill necessarily be very small whereby they will occasion practically nodamage, but this circumstance will not occur as a matter of fact. Whileit is true that the said ring is subject to occasional breakage when itis made of certain substances such as steatite, this breakage is in factof rare occurrence, and in any case will give rise to large-sized piecesall of which may be found upon dismounting the device. Under theseconditions the ignition device is or appears to be of a good use, byreason of the low voltage employed. This same circumstance enables theuse of the very small amount of play 38. ln fact, the operation of thisengine is such as to obviate any deposit of carbon when working underthe normal running conditions,

by reason of the high temperature ein ployed.. At starting, and'when theengine is cold, a deposit of carbon is certainly produced in such manneras to temporarily obstruct the space 38, but this is automaticallycleared away by reason of the high temperature. During the time when thesaid deposit remains, this carbon which is only recently formed appearsto lack the necessary cohesion to cause it to constitute a body havingsufficient conductivity to afford any considerable shunting of thecurrent, and the operation will therefore not be subjected to anyinconvenience for this reason.

The joint as well as the insulation of the central conductor areprovided for in a special manner. `When the ignition plug is subjectedto the action of the fiame, the entire length of the central conductoris at a substantially higher temperature than the main body 10 which iscooled by the outei air throughout the whole of the exterior portionthereof, this having a small diameter as shown in F ig. 3. This willrender it impossible to use either a cement or a joint in which endpressure is exerted by means of a simple screwthread. According to theconstruction herein employed, the conductor passes through the main bodywith the inter-position of the plastic insulating sleeve (of asbestos)15 which is only slightly pressed in order to provide for the loosesliding of the conductor. The spring 18 is caused to bear through theintermediary of the pressure member 16 upon the main body 10 in suchmanner as to constantly maintain the ring 14 well pressed between thebody and the head of the conductor. lf the said ring were free to move,it would soon become reduced to powder. rlhe sleeve 15 which is onlyslightly pressed is not sufficient to provide for a tight joint, butthis 'latter is obtained by the washer 17 which at i the same timeconstitutes an electric insulator and by the pressure member 16. Thebottoni surface of the member 16 is so designed that the total pressurevwhich. may be exerted upon the said'base by reason of Ithe innerpressure of the engine, and consequently the force of the spring 18counterbalancing this latter, shall correspond to a I tractive stressaffording all desired safety in the portion 13a 0f the centralconductor" this portion being subjected to the greatest strain by reasonof the temperature-and to a compression stress likewise affording alldesired safety for the ring 14. The spring 18 is sufficiently removedfrom the source of heat by reason of the long and narrow form of theignition plug, and is sufficiently cooled by the air not to lose itstemper. The current conducting terminal has preferably the form of aslotted end 19 rat-her than a screwthreaded end, for in case theconductor 13 should be rotated unawares by a nut engaging saidscrewthread, the filament might be damaged thereby,

The filament is secured at one end thereof to the main body and at theother end to the conductor by means of connecting plugs 12 made of analloy of a refractory nature which are sufliciently free from oxidationand preserve a sui'licient mechanical strength when heated, and havingsubstantially the same coefficient of expansion as the members (the mainbody and the said central conductor) wherein they are secured by means'of conical ends inserted after the manner of pins. The heads of the saidplugs have small apertures formed through the same wherein are insertedthe ends of the filament, these latter being then seated by means of asmall press. A more suitable electric contact may be obtained by a smallsoldered joint. at 40, ybut not at 41, inasmuch as in this case owing tothe danger of melting the lament, a more readily fusible solderingsubstance would be required.

Fig. 5 shows a modified form of construction of the terminal portion ofthe ignition plug. The central conductor 13 is provided with a slot 48at the end thereof for making suitable contact with the bell-shapedmember 42 having formed therein the apertures y43 for cooling the spring18 and secured firmly to the main body 10 by the screwthreaded ring 44.The said bell-shaped member is insulated by the washers 17 and 45. Thedevice is completed by the nut 46 whereby the wire 47 may be clampedwithout any risk of turning the central conductor 13, the free expansionand the tight fitting of the latter being secured by the same members asabove mentioned.

It is obvious'that this vinvention is not limited to the details ofconstruction hereinbefore set forth. f

Having now described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. An ignition device for effecting initial ignition in internalcombustion engines, comprising a combustion chamber having the shape ofa torus, a valve fuel atomizer extending into said combustion chamberand adapted to inject the fuel under the forin of a thin sheet at rightangle to the axis of the combustion chamber, a recess formed in the wallof said combustion chamber on a level with the valve of the atomizer,and an electric igniter with an incandescent filament mounted on saidcombustion chamber in such position that the incandescent filament islocated in the said recess, and may be reached by the atomized fueldischarged by the atomizer.

2, An ignition device for internal combustion engines comprising acombustion chamber having the shape of a torus, a valve fuel atomizerextending into said combustion chamber, a recess formed in the wall ofsaid combustion chamber on a level with the valve of the atomizer, andan electric igniter,

the incandescent filament of which is located recess in the body and isseparated by a small gap from the inner lateral wall of said recess, aninsulating layer surrounding the central rod, a ring made of aninsulating material, between the head of the rod and the bottom of therecess in the body, yielding means for pressing the head upon the ringand a filament extending from the body to the head of the rod.

3. An ignition device for internal combustion engines comprising acombustion chamber having the shape of a torus, a valve fuel atomizerextending into said combustion chamber, a recess formed in the wall ofsaid combustion chamber on a level with the valve of the atomizer, andan electric igniter, the incandescent filament of which is locatedwithin the said recess, said igniter comprising an igniter body having arecess in its inner end, a central conducting rod extending through saidbody and having'a head which extends by a short distance into saidrecess in the body and is `separated by a small gap from the innerlateral wall of said recess, an insulating layer surrounding the centralrod, a ring made of an insulating material, between the head of the rodand the bottom of the recess in the body, packing pressing memberssurrounding the rod, an insulating washer between said packing pressingmembers and the igniter body, a nut screwed on the rod, a spring betweenthe nut and the packing pressing members and a filament removablysecured at its ends to the igniter body and the head of the rod,respectively.

4. An ignition device for effecting initial ignition in internalcombustion engines comprising in combination: a working cylinder, acombustion chamber in communication with said cylinder, an igniter onsaid combustion chamber, means for supplying said igniter withA electriccurrent, current controlling means for interrupting said current, arelief cock on said working cylinder, means for operating said reliefcock `and means for operatively connecting said current controllingmeans and said means for operating the relief cock whereby the currentis broken when the relief cock is closed.

In testimony whereof I have signed my name to this specification.

EUGNE HENRI TARTRAIS.

